1. Field of the Invention
The present invention relates to an algorithm in the cellular search (CS) and more particularly to an algorithm for decreasing the number of unnecessary checkpoints in the cellular search.
2. Description of Related Art
In video coding systems, motion estimation plays a key role to remove temporal correlation between video pictures allowing information compression at reasonable video quality. At the same time, motion estimation is a very critical module of the encoder since it consumes most of the available computing time. Therefore, a fast and accurate block-based search technique is highly desirable to assure much reduced process delay while maintaining good reconstructed image quality. A straightforward block-matching algorithm (BMA) is the full-search (FS), which exhaustively searches for the accurate motion vector. The algorithm searches all locations in a specific search range and selects the position where the residual error of block-matching is minimized. Although it is optimal, such an approach results in a high computational cost due to the high number operations that are involved, and it is not suitable for real time and low power applications. To overcome this drawback, many fast block-matching algorithms have been developed, such as 2-D logarithm search (LOGS), three-step search (TSS), cellular search (CS), fast three-step search (FTSS), four-step search (4SS), and diamond search (DS), etc. The cellular search (CS) is an efficient one in fast computation while keeping reasonable picture performance.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional algorithms.